So I am looking for some opinion on cause of radiator death.

Backstory:
Radiator is genuine Toyota purchased and installed in 2012
Truck has seen mostly commuting miles the last few years.
Live in Tucson AZ Summers to 115 degrees.
Leaky hose cause upper inch or so of radiator to be empty of coolant for a couple days.(Thinking this is the cause)

The location in on the top of the radiator near the shroud.

 

Maybe just a weak spot in the tank soldering??

Have you ever changed the coolant since you installed the radiator?

Did you use only distilled water for dilution and make-up??

After a few years the corrosion inhibitors in antifreeze become depleted, coolant Ph changes, and destruction begins.

This is true even if the coolant appears clean and clear.

I flush and change every 3 or 4 years and after a couple years, I add a partial container of water pump lube/ corrosion inhibitor to strengthen the coolants partially depleted stuff.

 

a radiator shop can solder the top tank back on. Might be worth having the whole thing done. Keep it alive, don't go to the newer style aluminum.